Measurement of the efficiency of a water spray system against diesel oil pool and spray fires

Simple and robust test methodologies that make it possible to measure and quantify the effectiveness of water spray or water mist systems intended for "large" shipboard machinery spaces were investigated. Heat Release Rate calorimetry is usually the best method to measure the effectiveness of a water spray or mist system, although not all fire laboratories have access to such equipment. Therefore, there is a need to explore if other traditional measurement techniques can be used. Such methods include thermocouples, heat flux gages and Plate Thermometers. An additional method, the Pipe Thermometer, has been developed and investigated within the project. It consists of an insulated thin-walled stainless steel tube having an outer diameter of 103 mm with numerous thermocouples welded on the outside surface. The study, which was applied here on a water spray system, shows that the Pipe Thermometer is a possible method to use for evaluation of the efficiency of such system. It is definitely a better method than using heat flux meters or Plate Thermometer which were located at a distance from the fire source. The best correspondence between the measured data below the water spray system and the measured heat release rate was found between the measured gas temperature data and the measured convective heat release data. Consequently, there is no clear advantage of using the Pipe Thermometer (as mounted here) instead of traditional thermocouples at similar locations.